Simplify the following expression: $p = \dfrac{-9}{2n} - \dfrac{-7}{2n}$
Solution: Since the expressions have the same denominator we simply combine the numerators: $p = \dfrac{-9 - (-7)}{2n}$ Combine like terms: $p = \dfrac{-2}{2n}$ Simplify by dividing numerator and denominator by 2: $p = \dfrac{-1}{n}$